How should governments respond to Paris attacks? #bbcnolan

Mass murder on the streets of Paris has brought home the very real threat that Islamic State continues to pose. And it has added fuel to the debates on the war on terror, immigration and border controls. French President Francois Hollande called the attacks an "act of war" and vowed to be "merciless" in reply. But just how should the UK government respond? The Greek authorities say at least one of the attackers may have passed through the island of Leros with a group of 69 refugees. It is too soon to know whether a passport, registered in Greece, found at the scene of one of the attacks can definitely be matched to one of the attackers.